FG: Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures

Chairs

Hui Zhang, University of Alaska Fairbanks (hzhang@gi.alaska.edu)

Q.-G. Zong, University of Massachusetts Lowell (Qiugang_Zong@uml.edu)

Michael Ruohoniemi, Virginia Polytechnic and State University (mikeruo@vt.edu)

David Murr, Augsburg College (murrdl@augsburg.edu)

Description

The "Transient Phenomena at the Magnetopause and Bow Shock and Their Ground Signatures" focus group will employ both observations and simulations to investigate the transient phenomena at the magnetopause and bow shock and their ground signatures. The goal of this focus group is to provide a fundamental physical understanding of the transient phenomena at the magnetopause and bow shock including magnetic reconnection, FTEs, and Hot Flow Anomalies. This focus group encourages participation from communities interested in spacecraft observations (e.g., THEMIS and Cluster), ground-based observations (all-sky camera, radar, magnetometer), and global simulations. Coordinated multi-point observations are especially encouraged. This focus group is unique in the sense that it connects phenomena in regions ranging from the distant solar wind, bow shock, magnetosheath, and magnetosphere, all the way down to the ionosphere. Thus it will attract participation from a broad community including CEDAR and SHINE who do not normally interact.

Comparison of Transient Phenomena at the Bow Shock

	HFAs	SHFAs	Foreshock Bubbles	Foreshock Cavities	Foreshock Cavitons	Foreshock compressional boundary	Density Holes	SLAMs
Depletion in the density and magnetic field strength	Yes	Yes	Yes	Yes	Yes	Yes on the turbulent side	Yes	Yes
Compressions at edges	Yes	Yes	Only on the upstream edge	Yes	Yes	Yes	Yes	Yes
Presence of energetic (>30 keV) particles	Yes	Yes	Yes	Yes	Yes	No	Yes	No
Significant flow deflection	Yes	Yes	Yes	No	No	No	Yes	No
Significant plasma heating	Yes	Yes	Yes	Modest	No	No	Yes	No
Associated with an IMF discontinuity	Yes	No	Yes	Sometimes	No	No	Yes	No
Duration	Minutes	Minutes	Minutes	Minutes	Minutes	Minutes	Seconds	~10 s
Scale size	A few RE	A few RE	Up to 10 RE	A few RE	~ RE	~ RE	Ion gyroradius	Ion gyroradius
Generation Mechanisms	Interaction of IMF discontinuities with the bow shock	Interaction of foreshock cavitons with the bowshock	Kinetic interactions between suprathermal, backstreaming ions and incident solar wind plasma with embedded IMF discontinuities that move through and alter the ion foreshock.	Antisunward-moving slabs of magnetic field lines connected to the bow shock that are sandwiched between broader regions of magnetic field lines that remain unconnected to the bow shock.	Nonlinear evolution of ULF waves	Backstreaming ions result in increased pressure within the foreshock region leading to its expansion against the pristine solar wind and the generation of FCB.	Possibly due to backstreaming particles interacting with the original solar wind	Nonlinear wave steepening